Developments in treatment and outcome reporting of vascular thoracic outlet syndrome

This thesis explores the management of primary upper extremity deep venous thrombosis (pUEDVT) and, more specifically, venous thoracic outlet syndrome (VTOS) as a major underlying cause. Although VTOS is increasingly recognized, the optimal management strategy remains unclear due to limited high-quality evidence and the absence of validated outcome parameters for symptom severity. The resulting uncertainty has led to inconsistent guidelines and heterogeneous clinical practices. Given that pUEDVT and VTOS predominantly affect young, active adults between 20 and 45 years, the potential impact on quality of life and socioeconomic productivity underscores the need for systematic research. The central aim of this thesis is to evaluate the safety and effectiveness of current treatment approaches, develop new outcome measures, and provide direction for future studies.

Thoracic outlet syndrome is categorized into three subtypes depending on the compressed structure: neurogenic (NTOS), venous (VTOS), and arterial (ATOS). This thesis focuses on VTOS, defined as an objective compression or stenosis of the subclavian vein within the costoclavicular junction. Clinical manifestations include swelling, pain, fatigue, discoloration, and venous collateral formation. Depending on duration and onset, VTOS can be classified as acute, subacute, or chronic. Imaging modalities such as duplex ultrasonography, contrast-enhanced positional CT or MRI, and venography are essential for diagnosis. VTOS encompasses several subtypes, including McCleery syndrome (intermittent compression without thrombosis) and Paget-Schroetter syndrome (effort-induced thrombosis). The most serious complication is acute upper extremity deep venous thrombosis (UEDVT).

UEDVT is divided into primary (pUEDVT) and secondary (sUEDVT) forms. The latter is typically associated with intravascular devices or malignancy, whereas the primary type arises without an apparent cause and is frequently linked to VTOS. pUEDVT is rare, with an estimated incidence of 0.5–2 per 100,000 annually. Two main management strategies are used: (1) a conservative approach involving anticoagulation and compression therapy, and (2) an invasive approach consisting of thoracic outlet decompression (TOD), sometimes preceded by catheter-directed thrombolysis (CDT). Despite widespread use, the comparative effectiveness of these strategies remains uncertain due to a lack of randomized controlled trials and standardized outcome definitions.

This thesis aims to address these gaps. Chapter 2 presents a multicenter retrospective study comparing conservative and invasive treatment in current Dutch practice. Chapter 3 provides a systematic review on the optimal timing of TOD after CDT. Chapter 4 evaluates the controversial role of stenting in the thoracic outlet. Chapters 5 and 6 describe two international Delphi studies leading to the development of a validated upper extremity post-thrombotic syndrome (UE-PTS) scoring system. Chapter 7 assesses the role of intravascular ultrasound (IVUS) in diagnosis and follow-up, and Chapter 8 introduces the design of a national and international VTOS registry to standardize data collection and reporting.

Overall, this thesis aims to generate evidence, define uniform outcome measures, and establish a framework for improving the diagnosis, treatment, and research of VTOS and pUEDVT.